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Discussion Starter #1
Doing winter work on my projects. 1st one 351c 4bbl(71). This is my ride. Currently engine has unilite dist w/o vacuum, headers(big super comps), unknown cam(does have a decent lope to it) and everything else is stock. I'm not sure what the PO had in mind. Car was auto, am now installing 4spd, w 3.25 gears(open currently), and I am going to try port plates. I was curious what proven performance mods are recommended? I will use it for hot rodding around & maybe an occasional strip run to burn up hormones.
Project 2- 351w2bbl (69) totally stock XR7 vert for cruising.I would just like to "modernize"it so it's more spirited but still completely driveable so my wife can jump in and go. I am looking to go to dual exhaust but other than that I'm clueless. Any info would be greatly appreciated!!!
Thanks! Bob
 

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For the Windsor, considering the heads and bottom end are in good enough condition to warrant performance work. I would recomend a cam with about [email protected] for the intake and about [email protected] for the exhaust duration. or even up to 10 more degrees on the exhaust in comparison to the intake duration. This is because this head has a somewhat poor port flow balance, being bad on the exhaust's part. When choosing a cam, look for a cam with a fast ramp, with [email protected] the advertised duration should be about 260-270ish, any higher would not be a fast ramp. For the [email protected] you'd want about 268-278ish for advertised duration. For your lobe seperation, the wider the better, I would recomend 112 for this. Although Comp's Extream Energy series has Windsor cam with about the right specs for your application with 260/210 int, 268/218ex with a 111 lobe sep. This would still work well with the 111 since the advertised values are low. This would be the about the biggest cam to install in this application. You could even figure another 5 degrees less on each duration if you felt it'd better suit your desired use of the car.
The reason I pick these numbers for the cam is they offer good torque and hp through the mid range and start at a low enough rpm that you won't be forced to install a big gear in the rear and a high stall convertor like what you'd need to match a bigger cam.
Matching componants correctly is really what makes for a good running motor.
For the carb I would recomend a 600 Edelbrock. The reason for the Edelbrock is it is so much easier to tune then a Holley. I'm not saying Edelbrock is a more efficiant carb then a Holley, but when it comes to consistant running and holding a tune, the Edelbrock is better. Also they don't spontainiously leak. I have had plenty of Holleys and now run Edelbrocks on all my vehicles. For any carb, make sure you use two return springs, in the case if one breaks for safety issues.
You can go with either a stock 1969 4v Windsor intake or use an Edelbrock Performer. No other intake beats the stock 4v in torque up to 4000rpm's. The Performer will have just a little more hp on top.
With the ignition, my favorite ignition set up is a Ford Duraspark distributor used in conjunction with an MSD 6AL box. The duraspark is fairly easy to set up the timing range and curve. They are under 50 bucks at the auto parts store for a rebuilt distributor. The MSD is about 175 from Summit or Jeg's. To me, it is worth it. I have found that I was able to lean out the idle mix slightly while still maintaining a smooth idle. I did find that when I went from the Duraspark ignition box to the MSD, I didn't get any improvment in my cruising mileage. The duraspark box seemed to be set up really well for that range. Also, the MSD 6AL box has rev limiter protection. The cheaper MSD 6A does not has a rev limiter. It is easier to set up the Duraspark dist with an MSD then it is to set up the Duraspark dist with a Duraspark ignition box. So I'd recomend just to skip over the stock box since the MSD fully replaces it.
Run a K&N air cleaner and tune your car with it in place. If you tune with a paper element then go to K&N, you willhave to retune your carb----it happened to me. The K&N makes that much difference in an increase of airflow that I had to richen my carb to compensate.
I would not recomend headers. Even though your hp would be better, they are noisy no matter what muffler you have and they radiate excess heat. Usually you have to run that silly power steering drop bracket which will pull out the pressed in nuts after some driving. I am looking to go back to exhaust manifolds because the droaning noise which resonates off the header tubes just fills the car and really becomes a nusance in a short time of driving. I love getting in my convertible because it has exhaust manifolds----and all the sound comes out the back of the car. I can actually talk without rasing my voice to the person sitting in the passenger's seat---and they can hear me. I can't do that in my car with headers, I always have to yell. Headers are good when you are looking every last bit of HP. If you look at manifolds the flow restriction is quite appearant, but you have to think of the application the car will be used in. 99% of the time you will be cruisng and the exhaust gas load will be low and well within the capacity of the manifolds. The only time you'd have wanted headers is when your foot is to the floor and shifting at 5500 rpms. With the manifolds you may be losing 10-15 hp on the top in that 1% of when the car is at WOT. With headers, you will be losing some comfort for the 99% of the time and make it not so pleasant to go out on a cruise. Having the extra 8-10 degrees for the exhaust duration is partially for the sake of keeping the exhaust manifolds. The bare cylinder heads port flow relationship does warrant more exhaust duration, but only about 5 degrees. I like to add anoter 3-5 degrees for exhaust manifolds depending on what exhaust pipe diameter you are running. I'd recomend 2 1/4 pipe with a crossover. The exhaust shop must position the cross over far enough back as to not make a restriction when pulling out the trans. They can actually make a small H type crossover over that convertible reinforcement plate. 2 1/4 is the biggest you'd want to go with this engine combination, 2 inch would suffice because of the 99% versus 1%, and be easier for the exhaust shop to install. The smaller pipe will be quieter and offer somewhat better off idle torque.
The next mod after all this to the engine would be an overdrive transmission, be it an automatic AOD or a 5 speed manual---that is the ultimate for cruising on the highway.
I hope this offers some guidance in setting up your engine to make a great cruiser.
 

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Discussion Starter #4
thanks guys, that really gives me some areas to start on. I really like the rev limiter idea for the 4 spd too.
Can anyone give input on the cleveland intake? I've heard that the factory unit is a good one to stay with. True?
As far as exhaust is concerned, should I get a ready made H pipe and build from there, or will I run into problems because it's a vert? Appreciate the help, Bob
 

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hey Bob,

Sorry, I can't help with the Cleveland since it is in a Mustang----just joking. It really depends how much power you are looking to get and how much bottom end and such you want to give up. Phil Elder of the SSCC has a 351 Cleveland with a Torker intake, headers and a solid cam with 291/291 235/235 on a 111LS and makes a real 390 hp at 5900 rpms. That was tested on a roller dyno. The rear wheel hp was 330. Which is about what a good LS1 Firebird/Camaro makes and those cars are in the low-mid 13's all day long.
If you are serious about power, you need a solid cam. It is said that a solid cam is equal to running another 10 degrees on a hydrulic cam. I wouldn't bother with a roller, they are expensive and wear out the valve train much quicker---unless you are looking for every bit you can get and don't mid having a shorter life to your valve springs, giudes and such.
 

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Discussion Starter #6
I'm not looking to get too radical. I would like to stay with a hydraulic cam, stock springs, maybe rhodes lifters and roller rockers.
Any thoughts on intake and carb? Is the cast intake good?
Bob
 

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Baddad,

There were several different factory stock four barrel manifolds for Clevelands. First there was the cast iron square bore (also known as Holley pattern) intake for the 70- early 71 (engine code M). Then in late 71-72 they used a cast iron spreadbore (engine code Q) In 71 Mustangs only there was also the aluminum high-rise Holley pattern Boss 351 intake. For the 73-74 Q-codes, they also used a cast iron spreadbore intake, but those had the provision for the EGR passages (there's a channel in the carb surface). Well, actually, they had an aluminum EGR spacer plate that was sandwiched between the manifold and carb, but the intake surface has hot exhaust gasses running through it. All of the factory four barrel Cleveland intakes were of a dual plane design.

OK with all that said, you should stick with a dual plane design for streetability and crisp throttle response. Any aftermarket aluminum dual plane will be somewhat better than the factory at the higher RPM ranges, say above 4500. At almost anything below 5000rpm the stock cast iron intake is just as good.

Cam selection:

Stick with a dual pattern camshaft (intake and exhaust specs different since Clevelands really need help on the exhaust side. I have the old Crane 260 Econopower in BetaCat, the closer to stock of my two Cleveland 4Vs. .480/.506 lift, 260/272 duration. It has great throttle response and pulls well up to about 5200rpm. Above that it gets a bit winded and actually runs slower ETs. As it is it runs 14.40s.

Valve springs:

The stock springs are good for up to a .540 lift. However, depending on the mileage on your motor, chances are that your springs have lost their springiness. Replace them. They're cheap at around $60 for a set of aftermarket springs that are good for .600 lift.

Carb selection:

Stick with a vacuum secondary carb in the 600-650cfm range. I tried a 780cfm on BetaCat and again it went slower. I have a 600 vac secondary Holley on it now.

Rhoads lifters:

Not needed unless you are running a radical hydraulic and want to maintain your power brakes. The problem with leak-down lifters is that they allow the valves to smack the seats harder and you risk hammering the seats (wearing them out).

Roller rockers:

Good idea, but you'll need to convert your heads to adjustable rocker studs. Crane does make a conversion kit that I have just put on my more radical of my two Cats, AlphaCat. Crane also makes a roller trunion kit that uses the stock rockers but replaces the pivot with a roller unit. The problem with that is you still have the stock non-roller tip. Go ahead and get the rocker stud conversion and use true roller rockers. You'll be glad you did.

OK, That was my 38-1/2 cents worth....

Milo
 

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Discussion Starter #8
I do have the early square bore iron intake, and the 4300 autolite carb. In general the carb does good once warm, but I'm having a hell of a time balancing the choke setting. It's either very coldblooded to start, or so rich that it chugs till I play with the throttle. Frustrating!
I've read lots of good things about the 4100 series, but nothing about the 4300. Am I better served looking at aftermarket? Why should I look at vac secondaries? I don't have them now. Bob
 

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I have had good success useing factory 5.0 headers on early engines. They seal well, are dirt cheap, and offer a good compromize between manifolds and aftermarket headers.
 
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